Diastereoselectivity of tandem Michael addition–alkylation reactions: a convenient method for one-pot synthesis of α-branched 2,3-diphenylglutaric acid derivatives

α-Branched 2,3-diphenylglutaric acid derivatives with two adjacent chiral centres are easily obtained by one-pot Michael addition–alkylation sequences. The diastereoselectivity observed, which varies from outstanding to moderate and even low, was found to depend on the type of the metal intermediate (nitrile vs amide) and its γ-substitution pattern. A rigidly chelated transition state model that correctly predicts the sense of the asymmetric induction is proposed.